Web push technology is exploding -- even though there's no such thing.
Edmund X. DeJesus
Mentioning "push" technology could lead to a shove these days. That's partly because the people who support Web push technology--advertisers, information services--don't like to be perceived as pushy, even though they'd prefer to be in your face 24 hours a day. But mainly it's because there's no such thing as Web push technology and never has been. A pure push technology would put data--information, software, or advertising--on your screen or in your machine without you asking for it. But no alleged Web push techn
ology works that way.
There is, in fact, a spectrum of push technologies, ranging from actively subscribing to a service that will send you things practically continually, to receiving things almost solely
because you're on the Web. We'll look at these technologies and some of their implications.
It's Really Pull++
The way the Web works makes it difficult to implement a pure push technology. When you click on a Web address link, your client browser sends a request to the remote server that services the Web address associated with that link. That remote Web server finds the requested page and sends it off to your browser. Your browser (eventually) receives and displays that page. But
you
initiated the contact.
Even when there seems to be prolonged contact with a Web site--such as when you download a file-- you initiated that contact. And the remote Web server is just doing its best to send you that "page" (whose loose definition includes dow
nloads, streaming audio, and much else). The remote server didn't reach out and touch your browser uninvited.
The conclusion? The Web is primarily a "pull" medium: You decide what you want, your browser finds it--you pull it in.
This is not good enough for advertisers who want to get their messages in front of you, or information distributors who want you to subscribe to their services. It's like noncable TV: The ads and programming get to only whoever happens to be sitting in front of the box at that moment.
Given that all push technology involves something you did to initiate the result, the least pushy end of the spectrum is simple
notification
. For example, each day the eBay auction service (
http://www.ebay.com
) sends you e-mail to let you know the current highest bid on your merchandise.
E-mail is only one form of notification such services use. Other methods include an HTML page that you can check or even a beeper signal. For example, Netree's NetBuddy is a 16-bit Windows utility that looks at Web sites you're interested in and lets you know when they change. It's free. You don't even need a Web browser to use it. Surflogic LLC's Surfbot 2.0 offers more features, including a browser, for Windows 95. Even Microsoft's Internet Explorer 4.0 includes notification as a feature.
Depending on the service, you might be able to control how it notifies you, how often, and so forth. But overall, this kind of notification is not very interactive, obtrusive, or demanding of resources or throughput.
Up a notch on the pushiness spectrum is a
profile
. A profile watches Web pages or other sources of information, looks for matches to desired information, and forwards that information to you. You supply the criteria to the profile in the form of keywords, dates, values, rules of co
mparison, and other conditions. Profiles have more smarts than simple notification. There is a lot more processing going on behind the scenes. They are not just giving you a once-a-day report. Also, their contact with you is probably unpredictable since it is governed by whether the conditions you are looking for have been fulfilled. (Again, by contrast, notification may well be telling you the same unchanged information every day.) There's no telling when (or even if) the conditions you're looking for will occur. Who knows when that stock will hit 50?
The media that the profiles use to contact you are similar to those for notification. But they are probably more intrusive, since you may be looking for information that has definite time value. There is more interactivity here, at least in setting up the desired conditions, but still little impact on resources.
Not surprisingly, you can build whole services around
filtering the fire
hose of Web information. Examples of those t
hat have include Individual's NewsPage (subscription), Excite Live's NewsTracker (free), MIT Media Lab's FishWrap (free), Netscape's In-Box Direct (free), and Yahoo!'s My Yahoo (free).
Third in pushiness is
automatic pull
. There may be a set of Web pages you check frequently--stock prices, or weather reports, or Dilbert cartoons. Automatic pull will grab all these pages and store them for your later perusal. Although it doesn't seem pushy, automatic pull can actually be grabbing a lot of material and placing it in front of you. You may also receive these in the form of e-mail, or at least e-mail letting you know that these pages are waiting for you.
Automatic pull most likely occurs when you are on the Web, and it stores the grabbed pages locally. This requires more effort and interaction on your part, both in setting up what to look for and in reviewing what you receive. This is different from a profile: The actual Web pages are showing up for you to peruse. It also requires more resourc
es to store the information. And it may affect throughput if lots of people are doing it: If everyone in a company wants the final prices when the stock exchange closes, there's going to be a surge of contention for Web access.
Automatic pull products include First Floor's Smart Bookmarks, Folio's WebRetriever, ForeFront Group's WebWhacker, FreeLoader's FreeLoader (no cost), and Metz Software's Netriever.
Automated push
is the next level in pushiness, and most would agree that it
is
pushy. You subscribe to a service that publishes (pushes) information to you. The service probably publishes according to its own schedule of updates. This means that you have to be on the Web continually to receive the broadcasts. (Some of the products cache the information for you and forward it when you do hit the Web.) Typically, this also requires special client software on your end to send out periodic requests for updates ("polling" the service). Remember, on the Web you don't get anything unle
ss you ask for it. Automated push is more like "automated ask." What you get may be full-screen reports or running banners of headlines at the bottom of your screen.
There's lots of interactivity going on at this level. You're choosing which information stream to look at. You're refining your choices. The service may be refining what it sends you, or trying to guess what else it can entice you with. Advertisers are more interested in this than in most of the other types of push: Your choices give them information about you, including what you might like to buy or use. Plus, ads can be in the flow with the information.
Automated push also uses up more resources (saving information locally) and starts making big dents in throughput. Hooking up continually to the Web and getting fed regular hits of HTML can be a major drag on Web access, especially if many people in your organization are doing the same thing. Plus, all that material is sucking up network disk space. Administrators have complained abo
ut several products in this regard, including IFusion Com's Arrive and PointCast.
Most pushy of all is
channel-changer
technology. This sounds like what it is: You are plugged into one or more content delivery services and merely change "channels" to select weather, sports, financial info, or whatever. It's like cable TV on your PC. Again, your client browser must be sending a stream of "update me" messages to the remote server. This approach has the most interest of advertisers, for good reason: If you're looking at something all the time, they know you're going to see their message.
How They Work
How does all this stuff work? Different products use different technologies and strategies. Access to servers can happen in various ways. BackWeb can go with plain old HTTP, for example, or a protocol based on UDP. Castanet uses a proprietary method to perform transfers--based on TCP--of both Java code (that can bootstrap further processing) and differential downloads to the browser c
lient. Netscape's Netcaster (or Constellation), based on Castanet, uses a similar mix of Java applets, HTML, and HTTP.
Many of the tools, recognizing that they can place a significant drain on bandwidth, get smart about when they tune in. BackWeb's Polite Agent can tell when your connection to the Internet is idle and then start sending its channel information across. When you use the Internet again--by clicking on a Web link, for example--BackWeb stops transmitting until the connection is idle again. When that happens, the download picks up where it left off. BackWeb also compresses its content before downloading, minimizing traffic and network usage. PointCast uses idle moments to display a stream or a "screen-saver" broadcast of news and other content. McAfee's SecureCast does the same with virus updates, and software updates can travel the same way. If only part of the content has changed, only the changes need come across (a
differential download
). Even large files can be muscled across fa
irly painlessly.
Pushing Channel Buttons
The big guns in channel-changer technology aren't the advertisers. They are Microsoft and Netscape, both of whom have made this a priority.
It's not hard to see why. The days when sophisticated HTML-heads dominated the Web are over. The Web is becoming a commodity that the public logs onto. But it's a confusing place for them. The company that can point people to a nice, simple, TV-like nook where they can make simple selections, get information or entertainment they need or want, and keep them there--that company is going to own the market. And the viewers have no idea of the "constant-ask," nonpush technology that backs it all up.
There are many companies seeking a niche in this market. PointCast was the pioneer, with ad-supported channels, and it continues to innovate. Its technology can push information beyond firewalls, making it easier for browsers to access it. Marimba's Castanet downloads Java programs that enable applications and cha
nnels. Other products that take a similar approach include BackWeb Technologies' BackWeb, Intermind's Communicator, Verity's IntelliServ (part of its Search'97 suite), and Wayfarer's QuickCast.
These differ in what client and server software is necessary. And a corporate solution may involve a dedicated server that does nothing but forward requests to remote servers and handle requests from local browsers. That gets pricey, but it might save the network from getting bogged down by pushed information.
But there is no doubt that Microsoft and Netscape are leading this dance. Part of Netscape's new Communicator suite uses the Castanet software originally developed by Marimba. Microsoft's version of channel changing is called Active Desktop. Once, Netscape had an arrangement to carry PointCast's content. But since then, Microsoft and PointCast have made another arrangement to use Active Desktop to deliver PointCast's channels.
This may seem like fickleness, but it reflects the true nature of the
market and the technologies. Many are betting on channel changing to be the most popular push technology on the Web. And no one is betting that some outsider can elbow either Microsoft or Netscape out of the way. There will be two standards for this technology--Microsoft's and Netscape's--and most software providers and nearly all content providers are lining up behind one or the other.
Of course, there's no reason that the user can't run software that taps both technologies. As a result, all the content that either provides will somehow become available to whoever wants it.
Pushing the Envelope
Microsoft has come out with its own "standard" for channel management, the Channel Definition Format (CDF). CDF includes the capability for creating channels on a department or group level. Plus, CDF can automatically convert ordinary browser bookmarks into channels. Thus, sites you find useful can become more visible to others within your organization.
While defining standards can be trick
y, the policy of following Microsoft's lead is not usually a recipe for disaster. Some products, like DataChannel's ChannelManager, already support CDF.
Though some regard CDF as thin in details, the World Wide Web Consortium is considering it as a possible standard. Based partly on eXtensible Markup Language (XML), CDF defines certain properties that pertain to over-the-Web broadcast, including frequency of updating, limits on the amount of information sent, and server addresses that will be used.
Most observers feel that some standard is needed in this field because of the proliferating number of proprietary and incompatible technologies. Whether CDF is that standard has not been decided. One contrarian, not surprisingly, is Netscape, with its Java/HTML/HTTP approach. This may turn into a two-standard (oxymoron watch!) area.
The push technology in Netscape's Constellation has emerged from the chrysalis as Netcaster. Netcaster supports a channel model that can include Dynamic HTML, with la
yers, dynamic fonts, and canvas mode. Channel Finder gives users a way to look at and possibly subscribe to existing brand-name channels. (Yes, IS managers have the keys; they can customize the channels available and restrict access to company-specific content.) Netcaster also does automatic pull, grabbing and caching any site or channel for later viewing off-line. The whole shebang is still based on Marimba's Castanet.
Pulling a Fast One
There remains the pesky problem of keeping all that input from the Web from gagging networks. But there are ways to deal with this. For example, you could use a proxy server to field the incoming Web material and hold it for users to access. In fact, PointCast has realized the necessity for this in some situations and would be quite happy to sell you such a server.
Just altering the time and frequency of updating can make a big difference. You can usually set up your system to update automatically, which usually means that updates will occur when the ma
chine is idle. Your possibly vital news/weather/sports updates then become a kind of high-info-density screen saver. This effectively staggers access to the Web and prevents bottlenecks.
If the information you're looking for isn't extremely time-sensitive--like closing stock prices well after the exchange has shut down--the updates can occur overnight. You merely have to leave your machine on and configure your software to know when to refresh the information. This moves the Web access to off-peak times when contention is unlikely.
Simply reducing the frequency of updating can make a big difference. Do you really have to be checking in every five minutes? Once an hour, or once a day, might well suffice. Organizations can then establish the level they can safely tolerate.
The future of push technology will involve several competing phenomena. First, the number of external channels available will multiply, creating variety, choice, and confusion. Second, your enterprise will want its intranet
to become a channel. Third, all that traffic is bound to affect the Internet and cause more concern about its always-future collapse. Fourth, your enterprise will want to restrict what users can access, and how often. Last, you don't want all this extra traffic to gag your network to the extent that it interferes with normal work getting done (remember that?). There's no doubt that resolving all these different forces will indeed be a push.
Your best bet on push technology might not involve push technology at all. The IMAP4 mail protocol, already a standard, can handle HTML, Java, JavaScript, and so on. The right e-mail system could provide push-like technology without push. That might be all the push you need.
Where to Find
AirMedia
Newport Beach, CA
Phone: 800-247-6334
Phone: 714-737-5410
Internet:
http://www.airmedia.com
BackWeb Technologies
San Jose, CA
Phone: 800-863-0100
Phone: 408-437-0200
Internet:
http://www.backweb.com
DataChannel
Bellevue, WA
Phone: 206-462-1999
Internet:
http://www.datachannel.com
Excite
Mountain View, CA
Phone: 415-934-3611
Internet:
http://www.atext.com
First Floor
Mountain View, CA
Phone: 800-639-6387
Phone: 415-968-1101
Internet:
http://www.firstfloor.com
Folio
Provo, UT
Phone: 800-231-3654
Phone: 801-229-6700
Internet:
http://www.folio.com
ForeFront Group
Houston, TX
Phone: 800-475-5831
Phone: 713-961-1101
Internet:
http://www.ffg.com
FreeLoader
Washington, DC
Phone: 202-686-0660
Internet:
http://www.freeloader.com
IFusion Com
New York, NY
Phone: 212-352-4500
Internet:
http://www.ifusion.com
inCommon
San Mateo, CA
Phone: 415-345-5432
Internet:
http://www.incommon.com
Individual
Burlington, MA
Phone: 800-766-4224
Phone: 617-273-6000
Internet:
http://www.individual.com
Intermind
Seattle, WA
Phone: 800-625-6150
Phone: 206-812-6000
Internet:
http://www.intermind.com
Marimba
Palo Alto, CA
Phone: 415-328-5282
Internet:
http://www.marimba.com
McAfee Associates
Santa Clara, CA
Phone: 800-332-9966
Phone: 408-988-3832
Internet:
http://www.mcafee.com
Metz Software
Bellevue,
WA
Phone: 206-641-4525
Internet:
http://www.metz.com
Microsoft
Redmond, WA
Phone: 800-426-9400
Phone: 206-882-8080
Internet:
http://www.microsoft.com
NETdelivery
Ft. Collins, CO
Phone: 970-223-1110
Internet:
http://www.netdelivery.com
Netscape Communications
Mountain View, CA
Phone: 800-NETSITE
Phone: 415-254-1900
Internet:
http://home.netscape.com
PointCast
Cupertino, CA
Phone: 800-548-2203
Phone: 408-253-0894
Internet:
http://www.pointcast.com
Surflogic LLC
San Francisco, CA
Phone: 415-731-2732
Internet:
http://www.surflogic.com
Verity
Sunnyvale, CA
Phone: 800-424-3682
Phone: 408-541-1500
Internet:
http://www.verity.com
Wayfarer Communications
Mountain View, CA
Phone: 800-300-8559
Phone: 415-903-1720
Internet:
http://www.wayfarer.com
Yahoo!
Santa Clara, CA
Phone: 408-731-3300
Internet:
http://my.yahoo.com
HotBYTEs
- information on products covered or advertised in BYTE
illustration_link (33 Kb
ytes)
Push technology falls into two categories, based on whether the filter is on the server or on the client.
Edmund X. DeJesus (
edejesus@compuserve.com
) is a BYTE senior technical editor.
The Pull of Push
